A semiconductor chip is manufactured according to a semiconductor manufacturing process, and is then tested in the form of a wafer, die, or package using test equipment. Through the test, a defective portion or a defective chip may be sorted out. When some memory cells of a semiconductor chip are defective, the semiconductor chip is fixed by restoring such defective memory cells.
Recently, as a process of manufacturing a semiconductor chip, such as a dynamic random access memory (DRAM), has become increasingly refined. In such cases, features of the chip are generally smaller and more tightly integrated, such that errors are much more likely to occur during the manufacture process. Also, even if no error is detected during an initial test period, an error may occur during an operation of a chip. To solve this problem, various test methods and devices have been developed.